Lecture on ATP Production and Cellular Respiration

Introduction

• Discussion on morning routines, leading into cell function.
• Cells constantly perform processes, unlike humans who need coffee and time to wake up.
• ATP (Adenosine Triphosphate) is the energy currency for cells.
  • A nucleic acid with three phosphates.

Importance of ATP

• All cells, both prokaryotes and eukaryotes, need to produce ATP.
• ATP production can differ based on cell type.

Aerobic Cellular Respiration

• Focus on eukaryotic cells which have organelles like the nucleus and mitochondria.
• Overall goal: Produce ATP.

Equation Overview

• Reactants on the left, products on the right.
• Similar structure to photosynthesis equation but with different inputs and outputs.
• Glucose is broken down in cellular respiration to produce ATP.
• Example: Germinating bean seeds use stored glucose for ATP production until photosynthesis is possible.

Steps of Aerobic Cellular Respiration

Step 1: Glycolysis

• Occurs in the cytoplasm; does not require oxygen (anaerobic process).
• Converts glucose into pyruvate, yielding:
  • 2 ATP
  • 2 NADH (coenzyme for electron transfer)

Intermediate Step

• Pyruvate transported into mitochondria and converted to acetyl CoA.
• Produces carbon dioxide and NADH.

Step 2: Krebs Cycle (Citric Acid Cycle)

• Occurs in the mitochondrial matrix; considered aerobic.
• Does not directly consume oxygen but requires it for continuation.
• Yields:
  • 2 ATP
  • 6 NADH
  • 2 FADH2 (another electron transfer coenzyme)

Step 3: Electron Transport Chain and Chemiosmosis

• Occurs in the inner mitochondrial membrane; requires oxygen.
• Electrons from NADH and FADH2 used to generate a proton gradient.
• Protons travel through ATP synthase enzyme to produce ATP.
• Oxygen is the final electron acceptor forming water.
• This step produces the majority of ATP.
  • Estimates range from 26-34 ATP molecules per glucose.
  • Total ATP from all steps ranges 30-38 ATP per glucose.

Alternative Pathways

• Fermentation can occur without oxygen, less efficient but still produces ATP.

Importance of ATP and Mitochondrial Health

• ATP production is crucial; poisons like cyanide can inhibit it, leading to cell death.
• Research on mitochondrial diseases is vital for improving treatments.

Conclusion

• Emphasis on the significance of understanding ATP production.
• Encouragement for continued curiosity and learning.

Note: Additional reading suggested for the details of the Krebs Cycle and electron transport chain.